1. Field of the Invention
The present general inventive concept relates to an apparatus to seal a head chip nozzle of an inkjet cartridge in an image forming, and more particularly, to a nozzle tape to seal a nozzle surface of a head chip in order to prevent ink from leaking out of an inkjet cartridge during transportation and storage of the inkjet cartridge after the inkjet cartridge is assembled.
2. Description of the Related Art
FIG. 1 is a perspective view illustrating a state before a nozzle tape 16 is attached to a conventional inkjet cartridge 10, FIG. 2 is a cross-sectional view taken along a line I-I of FIG. 1, and FIG. 3 is a cross-sectional view taken along a line II-II of FIG. 1.
Referring to FIGS. 1, 2 and 3, a head chip 13 of the inkjet cartridge 10 is mounted on a head chip-mounting portion 12 formed at one side of a cartridge body 18.
A bottom sealant (not shown) for bonding the head chip 13 is applied on a bottom surface of the head chip-mounting portion 12, and a print head assembly provided with the head chip 13 and a flexible print circuit 21 connected to the head chip 13 is installed on the bottom sealant. In addition, a side sealant 19 is applied to seal a spaced gap between the head chip 13 and the head chip-mounting portion 12 in order to prevent ink from penetrating under the flexible print circuit 21 and conductors 22 to generate an electrical short between the conductors 22.
The flexible print circuit 21 is provided with the conductor 22 connected to the head chip 13 at its one end and connected to a contact pad 22a at the other end to transmit a control signal for ejecting the ink to the head chip 13. In this connection, a bead member 11 is applied to protect a connecting part of the head chip 13 and the conductor 22.
The ink is filled in the inkjet cartridge 10 to form a meniscus of the ink in nozzles 15. The inkjet cartridge 10 shown in FIGS. 2 and 3 is a color inkjet cartridge, of which the nozzles 15 are briefly illustrated to have the number less than the actual number, viewing from a longitudinal cross-sectional view of FIG. 2, and of which three nozzles 15 are formed to eject the ink of cyan, magenta and yellow, respectively, viewing from a lateral cross-sectional view of FIG. 3.
The nozzle tape 16 is attached to cover the flexible print circuit 21, the bead member 11, the head chip 13 and the head chip-mounting portion 12 to prevent the ink from leaking from the nozzles 15.
When the inkjet cartridge 10 is sealed by the nozzle tape 16, as shown in FIG. 3, air 14 is trapped under the nozzle tape 16 since the side sealant 19 is filled in the spaced gap formed between the head chip 13 and the head chip-mounting portion 12 but is not fully filled in the gap. The trapped air 14 is expanded by a temperature increase or a pressure drop caused by changes of external environments, and the nozzle 15 is opened as the nozzle tape is separated from a surface of the head chip 13 located on the nozzle 15 by an expansion force, thereby causing the ink leakage.
FIG. 4 is a cross-sectional view illustrating a state that the nozzle tape 16 is separated from a surface of a head chip by air expansion. Referring to FIGS. 1-4, a leaking ink 30 is penetrated between the nozzle tape 16 and the nozzle 15 to separate from each other due to a capillary phenomenon. As a result, the nozzle tape 16 loses its nozzle sealing function.
The leaked ink 30 not only causes various colors of the ink to be mixed but also breaks the meniscus of the ink due to a back flow through the nozzle 15, and the air is introduced into the head chip 13 through the nozzle 15, thereby causing a serious defect such as a loss of an ink supply function.
Meanwhile, Japanese Laid-Open Publication No. H06-320741, entitled “Method of Sealing Nozzle and Nozzle Tape used therein,” discloses a nozzle tape for preventing ink from leaking. The nozzle tape, e.g., an adhesive polymer tape having a slit, is attached to a printer head of a printer cartridge. Although the slit in parallel with a bead member is formed in order to solve a separation problem of the polymer tape due to a gap between the polymer tape and the nozzle surface and an ink penetration through the gap, generated by the bead member protruding from the nozzle surface, a nozzle tape separation phenomenon generated by an air trap in two spaced gaps, at which the bead member is not formed, could not be solved.